This invention relates to a composition for softening fabrics and in particular to such a composition which is particulate and capable of imparting a softening benefit to fabric during a wash process.
A number of materials have been suggested in the art for providing softening-in-the-wash benefits. These include certain classes of clay materials, especially smectite clays. Thus GB 1400898 (Procter and Gamble) suggests the use of smectite clays having a relatively high exchange capacity. While some fabric softening benefit can be obtained from detergent compositions containing fabric softening clays, this benefit is generally some way short of that which can be obtained by the application of softening materials to fabrics in the rinse step of a laundering process. Therefore, there is a desire to boost the performance of fabric softening clays in the wash. GB 2138037 (Colgate) proposes that the performance of fabric softening clays can be improved by the removal of grit therefrom and by their addition to the detergent composition as separate agglomerated particles.
Several disclosures in the art suggest that the performance of fabric softening clays is especially poor in the presence of nonionic surfactants. Thus, for example, GB1462484 (Procter & Gamble) proposes that in the presence of nonionic surfactants it is necessary to use smectite clays which have been rendered organophilic by an exchange reaction with quarternary ammonium compounds. GB 1400898, referred to above, is silent on the presence of nonionic surfactants. Also, European Patent Specification EP-11340-A (Procter & Gamble) teaches that, in a composition which includes a mixture of a smectite clay and a tertiary amine for softening-in-the-wash, when anionic surfactants are employed it is preferred that nonionic surfactants be absent, but if mixtures containing nonionics are used, it is preferred that the anionic forms the major part of the mixture.
It is apparent therefore that a prejudice has built up against the use of nonionic surfactants in combination with clays for softening-in-the-wash, especially in the presence of anionic surfactants.